Optical methods for imaging single biomolecules allow for exploration of their individual behavior and properties at the nanoscale level, which not only significantly advances knowledge of molecular biology and biophysics but also provide various diagnostics opportunities for biomedical applications. Imaging of single DNA molecules has been of particular interest as various diseases including cancer and neurological disorders such as Alzheimer's disease are associated with genomic alterations, including for example copy-number variations (CNVs). High spatial resolution and nondestructive nature of optical imaging methods are especially attractive for probing DNA-protein interactions or mapping genetic information from individual DNA molecules. These research and development efforts, however, have been mostly limited to advanced laboratory facilities using relatively costly, complex and bulky imaging set-ups, including for example confocal fluorescence microscopy, super-resolution microscopy, or label-free plasmonic imaging. Translation of these and other existing imaging techniques to field-portable, cost-effective and high-throughput instruments would open up a myriad of new applications in e.g., point-of-care (POC) medicine, global health and diagnostics fields, among others, and would also positively impact research and educational efforts in developing countries and resource-limited institutions, helping the democratization of advanced scientific instruments and measurement tools. To this end, mobile phones and other consumer electronics devices, including e.g., tablet PCs and wearable computers, have been emerging as powerful platforms to create cost-effective, portable and readily accessible alternatives to some of the advanced biomedical imaging and measurement tools. Mobile phones in particular have been experiencing significant advances in their optical imaging hardware, approximately doubling their space-bandwidth product every two years over the last ˜10-15 years, recently reaching to more than 40 million pixels in mobile phone-based digital camera systems. In addition to advanced optical interfaces that are now used in mobile phones, the computational power (now also including Graphics Processing Units, GPUs), data connectivity, massive volume (with >7 billion subscribers) and cost-effectiveness of mobile phones make them an ideal platform for conducting various advanced biomedical experiments and tests, including e.g., blood analysis, measurement of analytes in bodily fluids, flow-cytometry, among various others.
Despite all of these recent advances and progress, imaging of single DNA molecules on a mobile phone device has not be achieved, leaving it as one of the major remaining milestones in mobile phone based imaging and micro-analysis systems, mostly due to extremely weak signal-to-noise ratio (SNR) and limited contrast of single molecule samples in the optical portion of the electro-magnetic spectrum.